Remote Sensing: Introduction and Basic Concepts Basic concepts of remote sensing D Nagesh Kumar, IISc, Bangalore 3 M1L1 Fig. The energy source illuminates or provides electromagnetic energy to the target. Current bathymetric and ice LIDAR generally uses green light (e.g., NASA’s HSRL-1 LIDAR, with a spectrum of 532 nm). Common wavelengths of what we perceive as particular colours from the visible portion of the spectrum are listed below. • EMR is characterized by wavelength and frequency. Optical remote sensing satellites use reflected light to detect electromagnetic energy on the Earth’s surface. The energy interaction with the target depends on the target properties and the radiation. Humans with the aid of their eyes, noses, and ears are constantly seeing, smelling, and hearing things from a distance as they move through an environment. In visible light, typical remote sensing applications include the blue (450–495 nm), green (495–570 nm), and red (620–750 nm) spectral bands for panchromatic or multispectral or hyperspectral imaging. Violet: 0.4 - 0.446 µmBlue: 0.446 - 0.500 µmGreen: 0.500 - 0.578 µmYellow: 0.578 - 0.592 µmOrange: 0.592 - 0.620 µmRed: 0.620 - 0.7 µm. The light which our eyes - our "remote sensors" - can detect is part of the visible spectrum. The infrared region can be divided into two categories based on their radiation properties - the reflected IR, and the emitted or thermal IR. 2)Determines the thermal infrared response of an object (more absorbed energy across all wavelengths, the … The level of energy is represented by the electromagnetic spectrum, which is the range of energy that comes from the Sun or any other object in the Universe. The energy used in remote sensing of the earth comes from the sun. This depends on the property of material (structural, chemical, and physical), surface roughness, angle of incidence, intensity, and wavelength of radiant energy. This remote sensing method is known as Passive Remote sensing. For instance, "pink" can be considered a less saturated version of "red". The Remote Sensing is basically a multi-disciplinary science which includes a combination of various disciplines such as optics, spectroscopy, photography, computer, electronics and telecommunication, satellite launching etc. The portion of the spectrum of more recent interest to remote sensing is the microwave region from about 1 mm to 1 m. This covers the longest wavelengths used for remote sensing. It is important to recognize how small the visible portion is relative to the rest of the spectrum. The image is then interpreted to extract the informations about target. It suggests that EMR is composed of many discrete units called photons/quanta. Electromagnetic radiation (EMR) is a carrier of electromagnetic energy by transmitting the oscillation of the electro-magnetic field through space or matter. This is important since most natural EMR sources have very broad power spectra. It is also used to warn people about impending cyclones. The parameters that characterize a wave motion are wavelength (λ), frequency (ν) and velocity (c). The thermal IR covers wavelengths from approximately 3.0 µm to 100 µm. This radiation is just beyond the violet portion of the visible wavelengths, hence its name. Progressive stages in remote sensing are as follows: At temperature above absolute zero, all objects radiate electromagnetic energy by virtue of their atomic and molecular oscillations. It can be used for updating road maps, asphalt conditions, and wetland delineation. For the most purposes ultraviolet or UV of the spectrum shortest wavelengths are practical for... 2 Visible Spectrum. 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